“AquAdvantage® Salmon…advanced hybrid salmon designed to grow faster.” Could you get a starker strapline for the commodification of fauna? As the challenges of feeding an exploding global population continue to grow, branded animals like these GM salmon produced by biotech company Aquabounty Technologies could be commonplace, but what about the dangers? GM salmon made headlines recently, with some fearing threats to wild stocks in the Atlantic if they were to escape.

Hybrid grouper on the other hand get almost no media attention, yet they potentially pose a far greater danger. Hybridization is big business in South East Asia, where aquaculture businesses are interbreeding valuable grouper species in a bid to create a fast growing super fish.

Live grouper are highly prized in Hong Kong, Mainland China, Taiwan and other parts of South East Asia. They crowd tanks in seafood restaurants and are ubiquitous at Chinese wedding banquets and other formal occasions, where tradition demands they are served. Grouper can sell for more than US$100 a kilo and very large or rare specimens for much more. The market is huge – in Hong Kong alone, a staggering 3.6 million grouper are consumed each year.

But demand has led to rampant overfishing across South East Asia’s Coral Triangle bioregion. Fishermen often use cyanide to stun fish, destroying coral reefs in the process. According to a recent University of Hong Kong study, one in ten grouper species face extinction if current trends aren’t arrested.

On the face of it, advanced aquaculture techniques offer a way of fulfilling market demand while reducing the pressure on wild populations. Grouper are nurtured first in hatcheries from cultivated eggs and then in coastal cages or sometimes factories on land. The goal of hybridization is to achieve the holy trinity of rapid growth rates, resilience and superior taste.

“Hybridization of grouper isn’t new,” says Geoffrey Muldoon, a marine biologist with the World Wildlife Fund (WWF) “In 1996 the University of Malaysia in Sabah, Borneo produced a giant grouper/tiger grouper, dubbed the Sabah Grouper specifically for live reef fish food markets in Hong Kong,” he explains. The hybrid was a huge success with consumers and a boom followed. “Fast forward almost two decades and the science of grouper hybridisation has exploded,” says Muldoon.

In the early days, scientists only experimented with cross breeding natural grouper species. But then researchers in Taiwan went a step further. They began breeding hybrids with naturals and then different hybrids with each other. According to Irwin Wong, a live fish trader in Sabah, at last count, there were at least 12 new hybrid grouper variants and research is continuing in what has become a race to create a super grouper.

GM salmon are farmed inland, making escape relatively unlikely. But grouper are often kept in cages at sea.. “The fact is, hybrids may already have escaped,” says Wong. “If there’s a storm, fish often get free.” His fear is that two hybrids will breed in the wild. “If that happened, the effects on the ecosystem could be devastating.”

Grouper are hermaphrodites – or monandric protogynous hermaphrodites to give them their full title. Early in their growth cycle they are females, but in adulthood they can change into males. No one knows the precise trigger for this transformation, though size, age and environmental factors all play a part. Hybrid groupers in captivity are all female – but in the wild they could easily change sex, according to Wong. Which brings up the possibility of a sort of “X-Grouper” wreaking havoc with the food chain.

The current scientific consensus is that hybrid grouper are infertile – but since their reproductive cycle is still not fully understood, this is far from fact. At an Intergovernmental Forum of the six Coral Triangle countries in early 2013, experts agreed that “the hybridization of grouper has reached an alarming level, that escapes pose an as yet unknown risk to local wild populations and that this issue needs to be addressed as a matter of urgency.”

Experts are meeting again to discuss the issue at the world’s first World Coral Reef Conference in Indonesia on 16 May.

The live reef fish for food trade is a notoriously under regulated industry. It’s also highly lucrative – worth as much as US$1 billion annually. But consumption tends to follow a boom and bust cycle. Once the Sabah Grouper became readily available its per kilo value dropped dramatically. “The pursuit of a faster growing hybrid species is understandable, but there is little evidence to suggest patterns of consumer demand truly merit more efforts on hybridisation,” says Muldoon. He believes the industry needs to self-regulate for hybridisation to become viable. More research on both the science and the market for groupers is desperately needed – but criminal elements and an industry wide culture of secrecy makes this difficult.

In the meantime, the possibility of a “Frankenfish” wreaking havoc across reef ecosystems in the Coral Triangle is a real and growing danger.

This week I spotted the largest school of fish I have ever seen in Hong Kong. The grey mullets (Mugil cephalus) were attracted to a submarine seawater cooling outflow pipe that was discharging a grey liquid into the sea in western Kowloon. Each of the fish in the video below is 30-50 cm in length and I estimate there were at least 1000 of them.

I often see large mullets in that area. They regularly leap several feet into the air which is quite a spectacular sight. I have also seen an old angler at the Central ferry piers catching a 40cm mullet to the raucous applause of about 30 onlookers. The thing is the fish wasn’t hooked through the mouth but through the fin (quite a skill!) because it was swimming at the surface gasping and dying…
The behaviour of leaping out of the water according to some sources is a method mullets use to get more oxygen by storing air in their bodies so they can dive down into anoxic or low-oxygen water layers to catch prey others can’t. Grey mullets are known to be hypoxia-tolerant meaning they can tolerate low-oxygen environments better than other fish.

And here is another video of a large mullet just meters from Discovery Bay beach. The way it is gasping at the surface while swimming in its side is just how the fish was behaving which I saw caught at Central ferry pier.

So what does it mean if there is a large aggregation of fish which are known to be tolerant of low-oxygen environments and which are exhibiting low-oxygen behaviour? It’s a pretty good sign of a lack of oxygen – duh! What causes low oxygen in the sea? Nearly always eutrophication – the process whereby excess nutrients from normally man-made sources cause microscopic algae known as phytoplankton to grow into large blooms (and sometimes red tides). When these inevitably die off the mass of dead material on the seabed decomposes using up oxygen until there is so little that the seabed and lower depths become so-called dead zones (anoxic zone) where very few hardy species can survive.
So I suspected illegal waste-water discharge and made a report to the EPD (Environmental Protection Department) online including the above video (you can also report pollution via the government telephone hotline 1823).
Say what you want about the HK government, the civil service works! They followed up with a site visit to test the water and issued an order to the building management to repair their outflow pipe. Apparently the pipe was seawater cooling air conditioning outflow, but was discharging wastewater as well. Two days later after the problem was fixed and the fish were gone!

(Note: grey mullet is a very popular food fish in southern China and you will see it even in most supermarkets. But the vast majority is farmed – in case you were worried about your fish being from sewage outfalls!)

So what have HATS got to do with it?
HATS stands for the Harbour Area Treatment Scheme, a large sewage and wastewater treatment scheme designed to clean up HK’s notoriously filthy harbour. Setup in 2 phases, the first phase was successful enough to reduce the concentration of sewage to levels acceptable enough to allow the return of the New Year’s Cross Harbour Swim event. The annual event sees swimmers cross 1.89km from Lei Yu Mun’s Sam Ka Tsuen pier to Quarry Bay Park pier. First held in 1911 the event was stopped in 1978 because of health concerns.
However, in 2011 the EPD announced that water quality in the harbor, particularly in the eastern section where the race took place, had “shown significant improvement” and E. coli levels had decreased by 95 percent since 2001. Yet, the data from the EPD Shortly before the restarted race revealed that E. coli levels in the harbor were still twice the maximum acceptable level at Hong Kong bathing beaches. But it was still a big improvement.

The 2011 Cross-Harbour Swimming Race

The sewage levels are evaluated by measuring the concentration of the common gut bacteria Escheria coli(E. coli) in the samples as a proxy for all the other gut inhabiting and potentially dangerous bacteria and viruses in sewage.

However,the planned second phase of Hong Kong’s Harbour Area Treatment Scheme (HATS) has recently been put on indefinite hold. The upgrade would have boosted the capacity of the treatment works to remove nutrients such as phosphates from effluent. This would have reduce eutrophication and helped rehabilitate the dead zones. Excess phosphates are also linked to increases of toxic algal blooms.

Officials said the current chemical-based treatment system was enough to meet most water quality objectives and stressed the upgrade to biological treatment was not “critical” at this stage. The planned upgrade would deliver “only marginal improvements” to water quality in western Victoria Harbour and bring little benefit to near-shore pollution. Their priority was to cut off improperly connected pipes and crack down on unlawful discharges into the harbour off Central and Wan Chai.
When I first read that I was highly sceptical and thought the government was just trying to save money. But having seen illegal discharge from a major shopping mall and office complex directly into the Harbour I now think they actually have a very good point!

The HATS scheme overview

Denying the scheme was declared dead, assistant director of environmental protection Amy Yuen Wai-yin said that in terms of E coli levels close to the harbour’s shores, the upgrade was “not an answer”, citing water quality modelling results. The cost of the upgrade, according to the latest estimate based on 2012 prices, has almost tripled from the 2004 estimate of HK$11 billion to up to HK$30 billion. Perhaps then they are right to concentrate on cleaning up the illegal and accidental discharges of wastewater before tackling the finer points of more advanced clean up.

Jonathan Wong Woon-chung, another council member, said officials should clarify to what extent illegal discharges and improperly connected pipes contributed to water pollution. He also questioned whether the upgrade would have the intended effect, as improvements might be offset by cross-border pollution.

As a side note, the Kai Tak nullah, has been renamed Kai Tak river and has seen the return of grey mullets. This drainage channel in the old airport area is a catchment for several rivulets from the foothills of the Kowloon mountains, but was surrounded by rapidly growing factories and homes from the 1960’s to the late 1980’s which discharged all their effluent into it. It was so badly polluted and foul smelling that at one point there was a plan to completely cover it up and make it subterranean! Luckily science prevailed in the planning and there is now a scheme to remediate and green the area and especially the river. Obviously this wi take years, but the effort seems to already be beating fruits. See the project website here for more details.

The latest edition of the Sustainable Seafood Guide includes information for seafood consumers in Hong Kong shopping for responsibly farmed fish.

For the first time, the guide educates on the Aquaculture Stewardship Council (ASC) logo for responsible aquaculture.

“This is a great step forward in informing Asian seafood customers about the ASC. By choosing seafood with the ASC logo, shoppers can make a difference and help protecting oceans, vulnerable marine environments and local farm communities,” said ASC’s CEO Chris Ninnes.

There are currently 1,120 ASC certified seafood products available in 37 countries across the globe.

“Not only is our market share growing in Asia, but we have an expanding base of certified farms in the region including Indonesia, Malaysia, Taiwan and Vietnam; and we anticipate strong future growth,” Ninnes said.

The Hong Kong Sustainable Seafood Guide is produced by World Wildlife Foundation (WWF) Hong Kong.

The methodology that the guide is based on has been developed by WWF, Seafood Choices Alliance, North Sea Foundation and the Marine Conservation Society. Fish guides can now be found in 18 countries around the globe.

The ASC on-pack logo was launched in 2012. All ASC labelled products can be traced back through the entire supply chain to a responsible managed fish farm.

As the last thing the world needs is another “food blog” I decided to concentrate these fish posts more on the fish themselves, their marine biology and sustainability and fisheries. That said lets turn to the Conger Eel Muraenesox cinereus.

Its a member of the Eel group (which has 600 species!) and lives on soft bottoms down to a depth of about 100 metres where it feeds on small bottom fish and crustaceans. Its also sometimes found in estuaries and can even enter freshwater environments. They commonly reach length of 150 cm, but may grow as long as 200 cm. It occurs in the Red Sea, on the coast of the northern Indian Ocean, and in the East Pacific from Indochina to Japan. It has also invaded the Mediterranean through the Suez Canal. Conger eel is a major commercial species, with annual catches reaching about 350,000 tonnes in recent years. The countries reporting the largest landings were China and Taiwan. It is a traditional food in Japanese cuisine, where it is known as hamo and is wild caught but also cultured. Conger eel meat has been used as an ingredient in creating crab sticks.

It is marketed mainly fresh and is also used as bait for shark fishing. In China dried conger eel is apparently popular with eels 1m in length being split down the middle, gutted, washed in saline solution and then air dried – though I have never seen one in Hong Kong (so far). According to the traditional chinese medicine Wiki (TCM Wiki) the spawn – or eggs – (Hai Man Luan) of the Conger Eel is used to strengthen the body by means of tonics which reduce weakness, anemia, cirrhosis, hepatic adipose infiltration, neurasthenia. This is done by baking it to yellow, and then pounding it into powder, then taking 6~12 g of the powder orally. Another source (The Encyclopedic Reference of Traditional Chinese Medicine edited by Yang Xinrong) says it is used to with a detoxifying effect to treat malignant skin boils, scabies, and hemorrhoids with anal fistula (if you’re anything as curious as me when you read “anal fistula” …let me save you the trouble, of searching for it: here is the link to Wikipedia explaining it – enjoy…yuk!).
For the expats reading this : according to my 1962 book that is the inspiration for the fish posts, ‘Europeans’ (I think this is meant to include Americans) have only ever eaten 3-4 local fish species in Hong Kong. So should you bother expanding your food horizon with conger eel? Is this a good fish to eat? I can tell you it tastes just very nice with firm white flesh, but there are a lot of tiny bones that pretty much spoil the experience – for me anyway. From what I have read a lot of Chinese fish balls contain conger eel – probably along with other fish species – because ground down to paste and kneaded into fish balls the tiny bones are no longer a problem. So if you have ever eaten fish balls (perhaps in soup) , chances are you have had already tried conger eel without knowing it.
But the big question is – should you eat it? Is it sustainable? What does the WWF Seafood Guide say? It says – nothing, a big fat nothing. Conger eel is not mentioned at all. Zip. So now what? I have contacted Park’n’Shop again to get some more details on how they sourced their fish. But while we wait for an answer, I had a look around the internet to see what info is available on conger eel fisheries in China or Southeast Asia in general. According to the UN Food and Agriculture Organization (FAO) the catches of conger eel (and most other fish species) in China have skyrocketed in the last 20 years, going from 40,850 tonnes in 1990, to 372,704 in 2011! In Japan, the conger eel is caught by longlines and then transferred to fish farms to mature and they are making attempts to produce spawn so that they can farm this fish in future. And that’s about all you can find on the internet!
So we will have to wait and see what Park’n’Shop says. If the fish is caught by trawling, its a definitive no-no so AVOID. And if it is farmed or caught by lines, that’s is a bit better, but no guarantee that it is sustainable, so “THINK TWICE”. In the absence of information my verdict for now is a cautionary “AVOID”.

Flesh-eating disease – or necrotizing fasciitis as its known medically – is fast, nasty and often fatal. The fact that you can get it from contact with seawater makes it even more scary! Should we not swim in the sea anymore? Avoid all seafood? Stay away from beaches, boats and wet markets? These are the sort of questions raised recently. This thread from concerned residents on the Discovery Bay Forum is a good example.

But hold on a minute! The case discussed in the forum actually turned out to have nothing at all do with beaches, seawater, shellfish fish or anything else marine. A common Streptococcus bacteria which lives all around us on our bodies and in our guts was the cause of that infection.

So don’t panic! It’s a fascinating topic, and I want to look at the facts and the data first and then bring things into perspective with a look at the history of marine flesh-eating disease in Hong kong. What exactly is the danger? How worried should we be?

What is flesh-eating disease?
It is a serious bacterial infection of the soft tissue. The bacteria don’t actually eat flesh but the toxins they release while multiplying kill off living cells around them. This can cause death within 12 and 24 hours and about 20 to 30 percent of cases are fatal.

Several different bacteria can cause it. The most common cause is group A Streptococcus, which lives in people’s throats or on their skin. The man in Discovery Bay who recently died actually contracted a type of Streptococcus. But other bacteria can also cause it, including some which naturally live in your guts, on your skin, in marine sediment and seawater, soil, decaying plants and other places. One type called methicillin-restistant Staphylococcus aureus – best known from the news as MRSA – has also become important in the last 10 years because it is resistant to almost all antibiotics and is a major problem in hospitals. And it doesn’t have to be one type of bacteria that causes flesh-eating disease, they can also act together in what is known as Type II or polymicrobial necrotizing fasciitis.

So you can’t avoid these bacteria as they are everywhere in the environment. However, to cause an infection with flesh-eating disease they need a way into your body, because skin will not let them in, but an open wound will give them a chance to grow. Even once inside, your immune system is a great defence, as long as the bacteria do not enter your bloodstream directly. The majority of reported cases are in people who for several possible reasons have a weakened immune system: e.g. underlying illness, chronic diseases, tumours, diabetes, alcoholism or immuno-surpressing drugs and these cases are most likely to be fatal if the infection enters the blood stream. In fact one of the test of Vibrio vulnificus involves injecting the bacteria into the blood stream of mice to see if they die….sometimes science is a bit grim…but still, it saves lives.

Most but not all of the cases reported in Hong Kong recently were all caused by a marine bacteria Vibrio vulnificus, a relative of the bacteria that causes cholera (Vibrio cholerae).

What is the danger from Vibrio vulnificus?

The bacterium is everywhere, both geographically and in a variety of environments, although it occurs in relatively low numbers. It is naturally present in warm seawater and is not linked to pollution, although some studies have found higher numbers of this bacteria in tar balls (e.g. washed up tar balls from the Deep-water Horizon Oil spill), which attract many kinds of bacteria. It likes brackish (mixed fresh and seawater) and so is more common in estuaries and near river mouths. Because it likes warm water, it is more common in the summer months. Infection occurs through open wounds or through eating raw or undercooked shellfish or fish, but is not transmissible between persons. Anyone can be affected by wound infections, but persons with underlying medical conditions, especially liver disease, are at increased risk of blood stream infection and serious complications.

Vibrio vulnificus infections happen worldwide: the US, Japan, Southern Europe etc. In Taiwan, an annual number of 13-26 cases were reported during 1996-2000. The incubation period is usually 12 to 72 hours and the symptoms are intense pain, redness, swelling and rapidly developing tissue destruction usually associated with some form of wound. In persons with underlying medical conditions, especially liver disease, it can cause bloodstream infections with fever, chills, decreased blood pressure, blistering skin lesions and even death in severe cases. In healthy persons, it can cause diarrhoea, vomiting and abdominal pain. Sometimes, the swelling starts at the site of minor injury such as a small cut or bruise, but in other cases there is no obvious source of infection. Bloodstream infections in persons with liver disease are fatal about 50% of the time.

The infection is treated with antibiotics to kill the bacteria as soon as possible, but patients may also need surgery to cut away infected dead tissue or amputate the affected limb. Other than that, those who recover suffer no long-term consequences.

What is the dangerous it in Hong Kong?

In the last 7 years (since May 2005), there have been 51 reported cases of Vibrio vulnificus infections in Hong Kong – 37 Men and 14 women – an average of about 7 cases a year. To put this into perspective, in 2011 there were 6 reported cases of leprosy and in 2010 there were 124 reported snake bites in Hong Kong.

Infections occur predominantly in the summer months from May to October when the water is warm and conditions are right. Isolated cases also appear in colder months, but this could simply be because fish or shellfish is often kept in warmer tanks or because fresh seafood is now globally traded and flown around the world and imported from warmer regions.

Seasonal pattern of reported Vibrio vulnificus infections per month from 2005-2012. Infections peak in July and occur predominantly in the summer months from May to October.

Although the fatality rate is high at 27%, with 32% for men and 14% for women. The average age of infected persons was 66 for men and 71 for women.

From about July 2011 the Department of Health also reported if cases had underlying illnesses, and this shows that at least 53% of cases had underlying illness (3% did not have underlying illness and for the remaining cases the Centre for Health Protection’s press releases did not have enough information). I have compiled the data as a spreadsheet which you can download for free by clicking this link.

So basically, if you are older and/or weakened by illness or chronic disease you are at risk if you suffer a wound from handling seafood or have an open wound that comes into contact with uncooked seafood or seawater. Otherwise, there is no need to worry yourself greatly.

You should of course follow the CHP’s advice on prevention, which is more or less common-sensical:

* Avoid foot/leg contact with dirty water when visiting wet market;
* Avoid exposure of open wounds or broken skin to seawater or salty water;
* Wounds should be thoroughly cleaned and properly covered; and
* Wear thick rubber gloves when handling raw shellfish.
* You should seek medical advice promptly if you develop symptoms and signs of infection such as increasing redness, pain and swelling.

As V. vulnificus is so fond of warm brackish water, consider this: climate change is a leading cause of warming seas around the world, as well as of increased freshwater run-off from more erratic and heavier rain storms caused by the higher evaporation of seawater. This means that one of the effects of climate change could be an increase in infections, because the ideal conditions for V. vulnificus are becoming more widespread. There is a very direct and personal reason to cut your carbon foot-print, especially if you like shellfish and beach holidays…

Ah what a schoolboy marine biologist error! I thought I bought a Large Yellow Croaker Larimichthys crocea when really I bought a Small Yellow CroakerLarimichthys polyactis! You see the former occurs in Hong Kong waters and is on my list, but the latter is the occurs further north in the East China Sea, not in Hong Kong and is not even on my list! When it comes to Yellow Croakers size matters.
But I am not going to be academically pedantic about it and disqualify this meal. I can not imagine that the Large and Small Yellow Croaker taste very different, so this blog stands. Also I don’t want fish stocks to suffer an additional hit from my idiotic mistake…
I learned some valuable lessons from this: 1) read the label properly, 2) WWF’s Sustainable Seafood Guide is very inadequate as L. polyactis is not on there at all, and 3) ethically eating fish is very difficult!

This fish (Large Yellow Croaker) was on my list again marked ‘Think Twice’ – well, I thought twice, perhaps I should also have read the label twice!

What I was supposed to eat:Larimichthys crocea, called the Croceine croaker, Large yellow croaker or just the Yellow croaker, is a species of croaker native to the western Pacific, generally in temperate waters such as the Taiwan Strait. Males can reach 80 cm. Once an abundant commercial fish off China, Korea and Japan, its population collapsed in the 1970s due to overfishing.Fishing boats landed 56,088 t of Larimichthys crocea in 2008. The species is aquafarmed in China, and farms have experienced outbreaks of infections. L. crocea is an important enough commercial species to have its genome mapped.
WWF says: Yellow croaker sold in HK is from fish farms (mariculture). Fish farms can only be set up in designated places in Hong Kong and China. The industry is beneficial to local communities. However, the management measures in place to address the environmental impact of yellow croaker farms are weak, and enforcement is poor. The high density of fish promotes disease spread, land-based pond systems discharge the untreated pond effluent (excess feed, faeces) into the sea directly, and the feed consists of smaller often overfished and trawled species.

Herklots & Lin about the Yellow Croaker

What I actually ate:Larimichthys polyactis, called the redlip croaker, small yellow croaker, little yellow croaker or yellow corvina, is a species of croaker native to the western Pacific, generally in temperate waters such as the East China Sea and the Yellow Sea. They stay in shallow waters above 120 m but avoid brackish conditions. Individual males can reach 42 cm.
Once an abundant commercial fish off China, Korea and Japan, its population collapsed in the 1970s due to overfishing. Global catch has since rebounded, with 388,018 t landed in 2008. Salted and dried, they are a food product known as gulbi (굴비) in Korean. Yeonggwang gulbi is a prized delicacy, selling for over $100 a bunch.

My little beauties

And here are my two beauties before I took them home.

Anyway…What a beautiful fish! Look at that yellow underside! I needed two as it’s quite a small fish ~ 10 inches long.

My verdict: 6/10 – a decent fish. But it looks better than it tastes.
Fish was good, but had some more small bones in it and was quite small, so not as good as Pompano. A bit too soggy as it fell apart, but that’s more because I used a deeper steaming dish than last time so it cooked in its own juice more. Recipe was ok. Perhaps I should have had the salted or sun-dried version as it is very important as a salted or dried fish in China, and the Chinese must know best how to prepare their native fish.

The wife’s verdict: 6/10 (we agreed?)
Not as fleshy as the Pompano, more like other white fish. Recipe was better than last week.